> My server does verify the certificate of the target MX
But how do you know if the target MX is correct, and not controlled by an attacker? You can't really know for sure unless the receiver has secured their domain name with DNSSEC or published an MTA-STS policy.
But how do you know if the target MX is correct, and not controlled by an attacker? You can't really know for sure unless the receiver has secured their domain name with DNSSEC or published an MTA-STS policy.